Amazonian earthworks such as these are discussed quite a bit in Charles Mann's 1491, mostly in the context of dual hypotheses that the Amazon (and much of N. and S. America) was both far more heavily populated, and far more ecologically managed, than previously thought. It's a great and fascinating book, although not as data rich and scholarly as it could be.
I don't recall Mann having much description of what the earthworks were used for, although there were suggestions of some of them being fish corrals during high water events, I believe.
Yes, "both far more heavily populated, and far more ecologically managed", and for a far longer time. Perhaps for as long as 40 kiloyears. But relatively isolated, with just "low-bandwidth" communication with northeast Asia.
I wonder why things went so differently in Eurasia. Maybe bronze and iron technology? Jared Diamond stuff?
He does go into this a bit. Due to the ecology in the Amazon (a giant mud-filled floodplain), tools and buildings tended to be made of organic materials like wood & fiber rather than rock & metal as was more common in other areas of the world. As such, much of the evidence of these people would have rotted away by the time we started looking. Organic materials rot away real quick in a warm, wet climate.
OK, right. So ecology and terrain are the only records. Do we have any idea when populations crashed? Could it have been smallpox etc epidemics from European explorers?
Edit: Yes, Mann does indeed argue that. And also that isolation prevented tech spreading. I must read that book!
Mann mentions several instances of the following scenario, happening at various times across the Americas:
Year X: European explorer #1 sails up a river/crosses mountains/etc and discovers a vast empire, huge cities, and marvelous civilizations that his European nation might trade with. He brings pigs with him and trades them to the natives for their cool stuff.
Year X+20: European explorer #2 follows the path of explorer #1. Then he's all "WTF, there's nobody here." But explorer #2 does discover, e.g., the giant earthworks that explorer #1 said were there - it's just the city on top of the earthworks doesn't exist.
He postulates that in years X+1 to X+19, the smallpoxalypse occurred and civilization collapsed. The remaining survivors are just roving tribal bands trying to survive in the remains of their old civilization.
(To make a fictional analogy, consider the current civilization in Georgia and then consider the civilization depicted on the Walking Dead. Mann's hypothesis is that most of what we know about American Indians consists of observing the Walking Dead and then drawing conclusions about their pre-apocalyptic civilization.)
> (To make a fictional analogy, consider the current civilization in Georgia and then consider the civilization depicted on the Walking Dead. Mann's hypothesis is that most of what we know about American Indians consists of observing the Walking Dead and then drawing conclusions about their pre-apocalyptic civilization.)
Which is oddly fitting given the history of siphylis, which was likely carried over from the Americas and sometimes hypothesised to be the inspiration for zombies
He does have a tremendous amount of (IMO) anecdotal evidence as to when the various populations crashed, but at the end of the day I came away with a simpler conclusion: there just isn't enough reliable evidence to know what did or did not happen, but it seems very plausible there were huge populations of American peoples pre-columbus doing extraordinary things.
As per population crashing, his general thesis were:
- Disease spreads faster than explorers (people who would create records)
- For many reasons, European diseases were more deadly to Americans than American diseases were to Europeans.
- It's a lot easier to conquer a people if they are in the midst of an epidemic. Imagine an immune army invading Europe in the midst of the Bubonic Plague.
- In South America, severe climate events triggered massive wars that destroyed agriculture, leading to population collapse.
As per the tech, I would argue it did spread. Remember corn, potatoes, peppers, tomatoes, avocados, peanuts, sunflowers, and beans all came from Indians. As did the idea of a free people — the basis for America itself! We just don't tend to associate these ideas with "technology" as much as we do wheels and hammers. Much of the Eurasian technology we celebrate today was impractical and unnecessary in the Americas (What good is a wheel if you're climbing the stairs to Machu Picchu? What good is a horse if its hooves rot in the jungle?).
All that being said, I would recommend the book even though I have extremely mixed feelings about it. It was one of the most frustrating books I've read in recent memory, but at the same time, the material is extremely fascinating to me. I definitely came away realizing how ridiculous the history of Americas I learned in school was, but I can't say I came away with a better view of what the Americas looked like either. I'm really hoping for more research and writing on this subject — I think we have a lot to learn from the Old Americas, especially wrt to agriculture, agroforestry, and managing wildlands.
There's another theory floating around: That the bulk of the Amazon rainforest came into existence as a result of a millennia-long silviculture project taken on by the pre-Columbian Amazon people.
Edit: It seemed familliar b/c I read about it in other book. Conquistador by Levy touches on the underreported civ's and tech in the Americas before the Euros arrived.
> the dual hypotheses that the Amazon (and much of N. and S. America) was both far more heavily populated, and far more ecologically managed, than previously thought.
Reminds me of the Terence McKenna quote: The scene opens on a world that appears totally primitive. People are naked, people are orgiastic, people are nomadic. But when they close their eyes there are menus hanging in space. Culture has been internalized. Culture is supposed to be internalized. All this talk about virtual reality - people don't seem to notice - this is a virtual reality. These are all ideas - ideas that have been forced into matter so that we could live in a reconstruction of our imagination. And de-constructing these virtual realities in which we live is the only way to get back to some sort of baseline of what it is to be human.
These remind me of the circular homesteads I saw when flying over Africa. These homesteads were made of huts with a yard circled by a fence for protection and penning the domestic animals. In a rain forest, it would make sense to dig a small drainage pit around the whole yard, and for added protection like a moat.
I guess that's just the natural shape for a small fort - circular to enclose as much area with the least wall and ditch/wall because you need to dig the earth to build/reinforce your wall from somewhere and a ditch adds to the effectiveness of your wall?
They look very like the ancient settlements/enclosures that you get all over the UK - there are loads of them here in Scotland.
IANAA. I remember that it's very difficult to find ancient tools near China, because they probably used bamboo to build them.
In other places, the people used stones that are more archeological friendly. So it's possible to find the tools and even the shard of stones discarded while building the tools.
Is it possible that they can't find the tools here because they were made with some king of wood?
Tools might rot, but in general you'd expect to at least find middens, skeletal remains, teeth, scorched layers indicating a hearth of some sort, etc. There's non-tool markers for communities that will survive even in the rain forest.
I'm no archaeologist but here in NZ there often isn't a ton of archeology as much of what was used locally easily perishes with time - wood, flax etc. Possibly relevant but someone more informed maybe able to comment.
I'd say it gives a sense of the type of occupation of the land it is, city vs. village vs. local farmsteads, and thus an idea of the type of land use and cooperation that might have taken place?
I don't recall Mann having much description of what the earthworks were used for, although there were suggestions of some of them being fish corrals during high water events, I believe.